Evidence for evolution?

[SnapCount]

http://youtube.com/watch?v=rX_WH1bq5HQ

What do you think?

Shouldn't we expect to see more variety among monkeys and humans since they would have to be around for millions of years?

Isn't this better evidence against evolution than for it?

 

[gluadys]

http://youtube.com/watch?v=rX_WH1bq5HQ

What do you think?

Shouldn't we expect to see more variety among monkeys and humans since they would have to be around for millions of years?

Isn't this better evidence against evolution than for it?

Millions of years is not very long in geological time.

Look for more diversity in species separated 100s of millions of years ago.

 

[notto]

http://youtube.com/watch?v=rX_WH1bq5HQ

Shouldn't we expect to see more variety among monkeys and humans since they would have to be around for millions of years?

Can you provide any compelling reason why we would expect this?

Why would you expect more diversity than we already have?

 

[FishFace]

http://youtube.com/watch?v=rX_WH1bq5HQ

What do you think?

Shouldn't we expect to see more variety among monkeys and humans since they would have to be around for millions of years?

Isn't this better evidence against evolution than for it?

The separation time of humans and chimps (5-8mya) is about 325000 generations as a high estimate. Using an estimate of 2.5x10e-8 per (human) nucleotide, that tells us that each site in the genome has had about a .8% chance of mutating since humans diverged from chimps - assuming that the mutation rate and genome size has remained roughly the same. Even allowing for variation there, .8% allows us a lot of leeway. We wouldn't be surprised if a few changes where present, but we definitely expect these sites to be pretty much the same.

 

[SnapCount]

According to the video, there's no variety even though glutamic acid protein sequences are free to mutate.

 

[busterdog]

Why does every bony creature have only one head? Why only a single dorsal spinal Chord?

 

[juvenissun]

Why does every bony creature have only one head? Why only a single dorsal spinal Chord?

Good point.

Just like computers on board the space ship, there should be odd number of decision makers of at least three. Why couldn't life forms have a neuro system like that?

 

[Scotishfury09]

Good point.

Just like computers on board the space ship, there should be odd number of decision makers of at least three. Why couldn't life forms have a neuro system like that?

Too many chieftains and not enough indians?

 

[Assyrian]

Why does every bony creature have only one head? Why only a single dorsal spinal Chord?

 

[Mallon]

Why does every bony creature have only one head? Why only a single dorsal spinal Chord?

Because we know from experience that those aren't viable mutations. I really don't know what selective advantage having two spinal chords would have.

 

[sfs]

According to the video, there's no variety even though glutamic acid protein sequences are free to mutate.

Yes, but mutation isn't very rapid, and the three species are pretty closely related. The mutation in question (A<->G) is a transition mutation). Comparing humans and chimpanzee genomes, an A in one will be found as a G in the other 0.6% of the time. If you look at 12 specific possible mutation sites (as in the video), there is a 7% chance that one of them will have mutated -- so seeing all of them the same is indeed expected.

The other comparison in the video is between rhesus macaques and humans (or chimpanzees). Humans and macaques diverged around 35 million years ago, leaving ~6 times as much time for mutation.
Extrapolating from the human/chimp comparison, we would expect an A<->G mutation to occur for about 3.6% of available sites, and would therefore expect to have a 64% probability that among 12 randomly selected sites, none will have mutated.

In other words, no, we really wouldn't expect to see a lot of variation at these sites for these species.

 

[SnapCount]

But the video stated, "And we only compared 3 species", implying that the glutamic genes among other primates would be the same as well.

So, really, the prediction shouldn't be, "there wouldn't be enough time for divergence", it should be "there would be, more likely than not, to be at least SOME divergence."

 

[Biblewriter]

The separation time of humans and chimps (5-8mya) is about 325000 generations as a high estimate. Using an estimate of 2.5x10e-8 per (human) nucleotide, that tells us that each site in the genome has had about a .8% chance of mutating since humans diverged from chimps - assuming that the mutation rate and genome size has remained roughly the same. Even allowing for variation there, .8% allows us a lot of leeway. We wouldn't be surprised if a few changes where present, but we definitely expect these sites to be pretty much the same.

In my University years, I did research on the relative incidence of beneficial mutations as compared to detrimental mutations. After studying 5000 recorded mutations in the fruit fly, I found the following data:

90% of all the mutations were lethal.
90% of all the non-lethal mutations were crippling, such as missing limbs, etc.)
Not even one recorded mutation conferred an obvious reproductive advantage to the individuals that received it. I found one claim that one such mutation had been observed, but as this claim was backed by no specific information, it was dismissed as hearsay.

By the laws of probability, if an event occurs once in x trials, there is a fifty percent chance that it will occur in x/2 trials. Inverted, this well known law can be stated that any event that does not occur in x trials has no greater than a 50% probability that it occurs once in 2x trials.

So from this we can conclude that there is no greater than a 50% probability that the ration of beneficial to detrimental mutations is any greater than one in ten thousand. This data gives no indication of how much smaller the ratio might be. Only that there is no greater than a fifty percent probability that it could be any greater than one in ten thousand.

Combining this with the data from your post, we obtain a top side estimate for the rate of beneficial mutations to be 2.5 x 10e -12 per (human) nucleotide. This, divided by your 325,000 generations, yields a probability of not more than 8x10e -7 that a beneficial mutation would occur at any of these points, with no estimate of how much smaller the rate might actually be.

Conversely, if we were to assume that a transition from humanoid to the form we supposedly shared with chimps would require a beneficial mutation of as little as .01% of the genome, this would give us a minimum requirement of ten times your 5-8 million years for that transition to have taken place. This would take us back to the Paleocene era, just to get to that first transition!

To check out my data for yourself, see:
The mutants of Drosophila melanogaster
by Calvin B Bridges; Katherine Suydam Brehme

and

Genetic variations of Drosophila melanogaster.
by Lindsley D L & Grell E H.

 

[sfs]

But the video stated, "And we only compared 3 species", implying that the glutamic genes among other primates would be the same as well.

So, really, the prediction shouldn't be, "there wouldn't be enough time for divergence", it should be "there would be, more likely than not, to be at least SOME divergence."

Yes, as you look at more and more species, the expected number of observed differences will increase (although it doesn't increase much when you add new species that are closely related to ones you've already looked at, since there is only a small amount of additional time for mutations on that branch of the tree). The video did overstate the expectation of zero differences. (And looking at just 12 sites is not going to give you a very powerful test.)

 

[sfs]

In my University years, I did research on the relative incidence of beneficial mutations as compared to detrimental mutations. After studying 5000 recorded mutations in the fruit fly, I found the following data:

90% of all the mutations were lethal.
90% of all the non-lethal mutations were crippling, such as missing limbs, etc.)
Not even one recorded mutation conferred an obvious reproductive advantage to the individuals that received it. I found one claim that one such mutation had been observed, but as this claim was backed by no specific information, it was dismissed as hearsay.

Presumably you were looking at lists of visible mutants. The vast majority of mutations that cause visible effects on organisms are indeed deleterious. The vast majority of mutations, however, have no visible effect; most of these are neither deleterious nor beneficial, since the mutations have little or no effect.

In any case, you shouldn't expect to find many beneficial mutations for an existing organism -- they're already very well adapted to their environment, and any change that does much is likely to be bad. The easiest way to see beneficial mutations is to place an organism (preferably a rapidly reproducing one) in a new environment, where there is a major stress on the organism. Under those conditions, beneficial mutations appear very rapidly. The experiment is trivial to do with bacteria, and can be done in a biology classroom. Anyone who wants to put in some effort can see beneficial mutations occurring, which makes the claim that they never occur kind of silly.

(I do some work with malaria genetics, and one of the things the group is doing is running selection experiments on drug resistance: take a drug-sensitive strain, grow it up in the presence of an antimalarial drug until it develops resistance, and then compare the genetic sequences before and after to find exactly which mutations confer the resistance. In this case the mutations are beneficial for the parasite and very bad for their human hosts. Infectious diseases would be a lot easier to treat if beneficial mutations didn't occur.)

So from this we can conclude that there is no greater than a 50% probability that the ration of beneficial to detrimental mutations is any greater than one in ten thousand. This data gives no indication of how much smaller the ratio might be. Only that there is no greater than a fifty percent probability that it could be any greater than one in ten thousand.

Since your original estimate was based only on mutations of gross effect, it is irrelevant to the real world, where beneficial mutations are likely to be of small effect.

Combining this with the data from your post, we obtain a top side estimate for the rate of beneficial mutations to be 2.5 x 10e -12 per (human) nucleotide. This, divided by your 325,000 generations, yields a probability of not more than 8x10e -7 that a beneficial mutation would occur at any of these points, with no estimate of how much smaller the rate might actually be.

Ouch. Even granting your estimated limit on the beneficial mutation rate, this calculation is completely wrong. If the beneficial mutation rate is 2.5 x 10^-12 per nucleotide per generation, then the probability that a beneficial mutation will occur at any given site is 325,000 x 2.5 x 10^-12 x (number of genomes in the population). Humans seem to have had an effective population size of about 10,000 during most of their development, making the last factor 20,000 (since there are 2 copies of the genome per person). That makes the probability of a beneficial mutation ever having occurred 1.6% per site. There are 3 billion sites in the human genome, making the expected number of beneficial mutations in the entire genome 0.016 x 3,000,000,000, or around 50 million. I don't think that was the answer you were shooting for.

 

[shernren]

Why does every bony creature have only one head? Why only a single dorsal spinal Chord?

Because we know from experience that those aren't viable mutations. I really don't know what selective advantage having two spinal chords would have.

[spelling Nazi]

Cords, not chords!

[/spelling Nazi]

 

[Assyrian]

Godwin!

 

[SnapCount]

The key is not beneficial mutations. What's beneficial for one can be lethal to another.

The key is new structures.

http://www.apologeticspress.org/articles/2070


CHROMOSOMAL COUNTS It would make sense that, if humans and chimpanzees were genetically identical, then the manner in which they store DNA also would be similar. Yet it is not. DNA, the fundamental blueprint of life, is tightly compacted into chromosomes. All cells that possess a nucleus contain a specific number of chromosomes. Common sense would seem to necessitate that organisms that share a common ancestry would possess the same number of chromosomes. However, chromosome numbers in living organisms vary from 308 in the black mulberry (Morus nigra) to six in animals such as the mosquito (Culex pipiens) or nematode worm (Caenorhabditis elegans) [see Sinnot, et al., 1958]. Additionally, complexity does not appear to affect the chromosomal number. The radiolaria (a simple protozoon) has over 800, while humans possess 46. Chimpanzees, on the other hand, have 48 chromosomes. A strict comparison of chromosome numbers would indicate that we are more closely related to the Chinese muntjac (a small deer found in Taiwan&#8217;s mountainous regions), which also has 46 chromosomes.
This hurdle of differing numbers of chromosomes may appear trivial, but we must remember that chromosomes contain genes, which themselves are composed of DNA spirals. If the blueprint of DNA locked inside the chromosomes codes for only 46 chromosomes, then how can evolution account for the loss of two entire chromosomes? The task of DNA is to continually reproduce itself. If we infer that this change in chromosome number occurred through evolution, then we are asserting that the DNA locked in the original number of chromosomes did not do its job correctly or efficiently. Considering that each chromosome carries a number of genes, losing chromosomes does not make sense physiologically, and probably would prove deadly for new species. No respectable biologist would suggest that by removing one (or more) chromosomes, a new species likely would be produced. To remove even one chromosome would potentially remove the DNA codes for millions of vital body factors. Eldon Gardner summed it up as follows: &#8220;Chromosome number is probably more constant, however, than any other single morphological characteristic that is available for species identification&#8221; (1968, p. 211). To put it another way, humans always have had 46 chromosomes, whereas chimps always have had 48.

 

[SnapCount]

Of course, if the earth is say, much younger, then there wouldn't be time for any divergence, which is what we see in the video.

 

[sfs]

Of course, if the earth is say, much younger, then there wouldn't be time for any divergence, which is what we see in the video.

Of course, if the species were created separately, there's no reason for any particular result: the 12 sites could be all the same, all different, or anywhere in between. Common descent, on the other hand, offers a fairly specific prediction: there should be no more than one or two differences. This is why common descent was a useful scientific hypothesis: it offers many specific predictions.

By itself, this test is not very interesting. For a look at larger-scale differences (where you do indeed see divergence between species), you could look here, which I wrote a while ago.